David M.-T. Kuo

Challenges in 1 Teradot∕in.2 dot patterning using electron beam lithography for bit-patterned media

Electron beam lithography presents a great opportunity for bit-patterned media (BPM) applications due to its resolution capability and placement accuracy. However, there are still many challenges associated with this application including tool availability, resist capability, process development, and associated metrology needs. This paper will briefly discuss these challenges and show the results of sub-25 nm pitch (1 Tdots∕in.2) patterning from both a simulation and experimental perspective. The simulation results indicate that the energy contrast between the exposed and unexposed areas goes down quickly as the pitch size gets smaller and smaller, making it more difficult for image formation of high-resolution dot patterning. The strategy to overcome this issue is to optimize the development process, which aims at increasing the resist contrast and enlarging the process window. By using this approach, the authors have successfully demonstrated a pitch resolution down to 18 nm for a positive-tone resist Z...

Thermoelectric and thermal rectification properties of quantum dot junctions

The electrical conductance, thermal conductance, thermal power, and figure of merit

Fabrication of a germanium quantum-dot single-electron transistor with large Coulomb-blockade oscillations at room temperature

(ZT)

Step and flash imprint lithography for manufacturing patterned media

of semiconductor quantum dots (QDs) embedded into an insulator matrix connected with metallic electrodes are theoretically investigated in the Coulomb blockade regime. The multilevel Anderson model is used to simulate the multiple QDs junction system. The charge and heat currents in the sequential tunneling process are calculated by the Keldysh Greens function technique. In the linear-response regime the

Tunneling current spectroscopy of a nanostructure junction involving multiple energy levels.

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Theoretical modeling of dark current and photo-response for quantum well and quantum dot infrared detectors

values are still very impressive in the small tunneling rates case, although the effect of electron Coulomb interaction on

Enhanced thermal stability and emission intensity of InAs quantum dots covered by an InGaAsSb strain-reducing layer

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Integration of nanoimprint lithography with block copolymer directed self-assembly for fabrication of a sub-20 nm template for bit-patterned media

is significant. In the nonlinear-response regime, we have demonstrated that the thermal rectification behavior can be observed for the coupled QDs system, where the very strong asymmetrical coupling between the dots and electrodes, large energy-level separation between dots and strong interdot Coulomb interactions are required.

Servo-Integrated Patterned Media by Hybrid Directed Self-Assembly

A simple and complementary metal-oxide-semiconductor-compatible method for fabricating germanium (Ge) single-electron transistors (SETs) is proposed, in which the Ge quantum dots (QDs) are naturally formed by selective oxidation of Si0.95Ge0.05∕Si wires on a silicon-on-insulator substrate. Clear Coulomb-blockade oscillations, Coulomb staircase, and negative differential conductances were experimentally observed at room temperature. The tunneling currents through the Ge QDs were simulated by the Anderson model with two energy levels. Analysis of the current–voltage characteristics indicates that the single-electron addition energy of the Ge QD is about 125meV.

Theory of spin blockade, charge ratchet effect, and thermoelectrical behavior in serially coupled quantum-dot system

The ever-growing demand for hard drives with greater storage density has motivated a technology shift from continuous magnetic media to patterned media hard disks, which are expected to be implemented in future generations of hard disk drives to provide data storage at densities exceeding 1012 bits/in.2. Step and flash imprint lithography (S-FIL) technology has been employed to pattern the hard disk substrates. This article discusses the infrastructure required to enable S-FIL in high-volume manufacturing, namely, fabrication of master templates, template replication, high-volume imprinting with precisely controlled residual layers, and dual-sided imprinting. Imprinting of disks is demonstrated with substrate throughput currently as high as 180 disks/h (dual sided). These processes are applied to patterning hard disk substrates with both discrete tracks and bit-patterned designs.